Symptom - no input:
 | Input relay: LED on with 0VAC at screw |
FIX - Replace bad input relay.
| Input relay: LED off with 0V
AC at screw |
FIX - no input signal from external
device: have an electrician trace the fault and repair it.
Symptom -
input active
| Input relay: LED off with
120V AC at screw |
Probable Cause (in most
likely order)
| Replace bad input relay.
|
| No 5V
AC at relay rack:
 | Check fuse on power supply.
If bad, find fault and replace fuse.
|
|
| Disconnect and reapply power
to the power supply.
| If output voltage is still
low, disconnect power wires at relay rack. |
| If still low, power supply
is probably bad - replace it. |
|
|
